1. Field of the Invention
The present invention relates to an automatic power generating type flowmeter having a power generation mechanism for oscillating a signal corresponding to a flow rate of fluid flowing through a specific location.
2. Description of the Related Art
An automatic power generation type water meter is known which is employed as a remote measuring meter having a power generation mechanism adapted to oscillate a signal corresponding to a flow rate of fluid flowing through a specific location without the need of any external power source. The water meter includes, main and auxiliary casings which are separately formed. The main casing has a flow inlet and a flow outlet. The auxiliary casing has a cylindrical shape and accommodates a receiver unit and a power generation mechanism or transmission unit. An impeller is arranged partway of a passage in the main casing and has a rotation shaft coupled through a first speed-reduction gear group and magnetic coupling to a second speed-reduction gear group in the auxiliary or receiver casing. The power generation mechanism is coupled to the second speed-reduction gear group. The power generation mechanism rotates a magnet, producing a magnetic flux change in a core of an electromagnetic coil and hence an induction magnetomotive force.
In the automatic power generation type water meter so constructed, in addition to the main casing, the receiver unit casing is mounted in place with the transmitting unit incorporated therein. The magnet and overlying electromagnetic coil's core of the power generation mechanism are arranged coaxial with each other in a direction of their height. Therefore, the transmitting unit and hence the receiver casing becomes higher. As a result, the transmitting unit-equipped water meter becomes bulkier in the height direction, thus occupying a larger area for installation.